790 Reported Clutch failures - My 12k mile examination

Discussion in 'Parallel World (790/890)' started by windblown101, Nov 10, 2019.

  1. chain

    chain Go Fly Supporter

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    Clutch failure at 922 miles.
    Due to clogged oil port at center of clutch hub.
    Clutch plates dried and fried

    Attached Files:

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  2. chain

    chain Go Fly Supporter

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    make sure your service tech cleans this port at first service
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  3. AdvRonski

    AdvRonski They call me......Ronski

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    Sorry, but if there actually was a lack of oil, it would not cause a clutch failure. There are motorcycle engines that run a dry clutch, and while they may be a little noisy, they work just fine. Most of the internal engine parts do require lubrication to operate, as they roll, slide, or spin, but clutch plates clamp together, and generate friction despite the presence of oil.
    Just another example of how quickly clutch plates can burn when they do not have sufficient free play, and a rider doesn't notice until it's too late.
  4. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Covered under warranty?
  5. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Yeah, but they are designed with different friction materials, etc.
  6. chain

    chain Go Fly Supporter

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    Free play was good
    Cable end loose at Rod.
    first thing I checked at the slightest slip. took it to Carter Motorsport in LV, they inspected Plates, reassembled and sent me on with a shrug.
    Trailered to 29 Palms, unloaded, riding up the hill into Joshua Tree on my way to Baja, clutch started slipping again. By the time I made it black to camp (10 miles) clutch was toast.
    Yes, checked free play as soon as it started slipping 2nd time as well.

    The good folks at 3 Brothers Racing in Costa Mesa,CA went above and beyond to put me back on the road.
    Three KTM techs that looked at the bike seemed confident that lack of oil was the issue. ‍
    KTM agreed.

    It looked like Threadlock from assembly was clogging the port.
    The manual “recommends” cleaning the port at first service, Clean yours or don’t, doesn’t matter to me if you wanna run a dry clutch. Just hoping to save someone else the pain.
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  7. Velociraptor

    Velociraptor TrackBum Super Supporter

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    I changed my stock clutch pack for the Rekluse torq drive kit. Works great but now much harder to find neutral. I just emailed than a question about that. My stock clutch looked fine. I wonder if you have the port clogging and change to Rekluse without fixing the oiling problem that you will eventually fry the Rekluse clutch too. Probably. Just may take longer. I still may pull that oil port piece and have a closer look but since I have had no clutch issues it is probably fine.
  8. Kinkysmurf

    Kinkysmurf Adventurer

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    Just what I'm talking about in the 790 Adv thread, this bit is important. Sorry to hear about the loctite in there, heard that before too. I might have look at mine soon.
    Glad KTM are doing warrantry. Good luck.
  9. AdvRonski

    AdvRonski They call me......Ronski

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    Still not buying that explanation. The first 950 engines came with a closed oil jet, which was later changed to a .30mm jet, the same size the 790 uses. The reason the jet was added was not slippage, but rather the opposite, with grabby engagement and difficulty finding neutral being common complaints. Some people drilled out the jets as large as .50mm, with the excess oil also making neutral difficult to find. A lack of oil could cause the clutch to overheat more readily, but that would require the clutch to be slipping for long enough to build up that heat, which still leads back to improper free play adjustment.
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  10. Kinkysmurf

    Kinkysmurf Adventurer

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    You may well be right @AdvRonski, I understand your explanation and its sounds logical, but I dont have your experience in these clutches to call bullshit on the guy. If KTM are doing warranty, I wonder why, when they have denied others.
  11. AdvRonski

    AdvRonski They call me......Ronski

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    I wonder if they are trying to counter the bad press they have gotten from stiffing the other poor bastards. I know in the car biz, sometimes it would depend on how much is left in the warranty budget for the zone. At least in goodwill cases.
  12. blackSP

    blackSP 62 6c 61 63 6b 53 50

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    Wet clutch, dry clutch. Totally different design. If a wet clutch runs dry it will heat up quickly and burn, it needs oil for cooling. Dry clutches are developed to deal with that. Tons of stuff written on this topic, Google it.
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  13. 1coolbanana

    1coolbanana Long timer

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    So has anyone enlarged the jet orifice from 0.3 to 0.5 mm and observed/felt any difference?
    This is common practice on 9XX's (done plenty) and the only downside would be neutral becomes more difficult to find when passing the 0.5mm threshold.

    Looks like I might have a go at that over the next few days unless anyone has a good reason no to.
  14. Thumper Dumper

    Thumper Dumper Been here awhile

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    Firstly let me say "don't fix what isn't broke"
    If you are having an oil starvation issue maybe check the jet for a blockage first, by increasing the jet size to 0.5mm you are almost doubling the size.
    A larger jet can cause lower oil pressure elsewhere in the system which in turn may cause a failure elsewhere in the motor that probably won't be covered by warranty .
    I removed my clutch pack after about 3000km because I installed a Rekluse and my clutch plates had plenty of oil on them.
    Considering that the jury is still out on the cause of the failures if I had the standard clutch I would just check it from time to time and ensure that the free play is adjusted correctly.
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  15. 1coolbanana

    1coolbanana Long timer

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    True.
    I may take it out just to check its clean and see what size it is and go from there.
    Bike is new with only 300 km, having its first service in a couple weeks but I can guarantee they wont be checking the jet.

    The difference between 0.3 and 0.5mm is about 2.5 times greater area/possible flow.
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  16. AdvRonski

    AdvRonski They call me......Ronski

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    Not at all true. Same basic design, slightly different materials. The only way a clutch will heat up is if it's slipping. This slippage has nothing to do with the presence of oil. If the rate of slippage is bad enough, no amount of cooling oil is going to save it. You need to have enough situational awareness to notice the slipping when it starts, and adjust the clutch cable to stop it, or it will go away very quickly.
    I still place the cause for these failures as a lack of adequate free play. The fact that some of these guys have ridden them to the point of complete destruction isn't surprising to me.
    I was an automotive Master Technician for 40 years, and many times on a ride, other riders would ask me to ride their bikes to evaluate some issue or another. What I found, was that many riders had only a very vague idea of what their bike was doing, I suppose because all of their focus was on the many external challenges involved in riding off-road.
    Anyway, in my opinion, as far as this chicken-and-egg situation, is the slippage has nothing to do with the oil supply, and can't provide adequate cooling once the slippage passes a certain level.
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  17. TrailTrauma

    TrailTrauma Nemophilist

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    Love it! So true. A rider has to eventually rise to a certain level of competence before his or her attention can be redirected elsewhere. Then they need to have some rudimentary understanding of a bikes systems before they can marry that awareness to solutions. In your case, your background puts you light years ahead of the pack. Definitely the guy to have as a riding partner in the group. I think by helping as you do, the ones paying attention all turbo charge their own understanding of systems/bikes, which then spills over to the rest of the group in your absence.
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  18. windblown101

    windblown101 Long timer Supporter

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    Still.... In my memory with is admittedly flawed I have never seen so many reports of low mileage clutch failures much less the startling number of clutch friction discs turning into shrapnel. The high number of failures could be a number of things. Certainly not staying on top of lever adjustment is one. Heck, some might confuse the gap created by the lever position adjustment gap as being freeplay gap. Another is the very specific way the lever at the motor should be adjusted to ensure it allows the motor side release arm to let the clutch fully lock up.

    At the end of the day a burned up clutch is not earth shattering nor new, but that sharpnel thing though.... that sucks and KTM will hopefully do a redesign, not because I think they owe everyone a new clutch but because grenading clutch plates ain't cool.
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  19. kubcat

    kubcat Been here awhile Supporter

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    How many unique cases have you read about? I have only heard of a few (less than 5) very vocal cases of clutch failure, which have been cross posted all over the interweb echo chamber, making them seem like they are happening to everyone everywhere. Has anyone taken the time to log the incidents objectively yet?
  20. Kinkysmurf

    Kinkysmurf Adventurer

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    This was something I was thinking to. Hard for experienced guys to imagine....Ive been adjusting clutches for 40 years, it aint rocket science.
    I agree something seems wrong, In decades of riding and racing, I have only ever had unwanted clutch slip once and you know when does. I have rebuilt clutches and replaced baskets. But these "slipper Clutches" are new to me. Been off bikes for 10 years after a fall at work and breaking my neck.
    Can the Slippers be generating heat when it " slips" to counter excessive engine braking. ? Im think Supermoto style riding, street hoolgans
    windblown101 likes this.